CN116139908A

CN116139908A - Catalyst for generating singlet oxygen by targeted activation of persulfate and preparation method and application thereof

Info

Publication number: CN116139908A
Application number: CN202310181566.8A
Authority: CN
Inventors: 季民; 王如梦; 翟洪艳
Original assignee: Tianjin University
Current assignee: Tianjin University
Priority date: 2023-02-24
Filing date: 2023-02-24
Publication date: 2023-05-23
Anticipated expiration: 2043-02-24
Also published as: CN116139908B

Abstract

The invention discloses a catalyst for generating singlet oxygen by targeted activation of persulfate and a preparation method and application thereof, belonging to the technical field of oxidation treatment of typical new pollutants in water. Polyaniline is synthesized on the surface of graphene oxide in situ, and then thermal reduction annealing is carried out in an inert environment, so that targeted activated persulfate is preparedCatalysts for singlet oxygen. The preparation method of the catalytic material provided by the invention is simple to operate, mild in condition, strong in repeated operability and easy to realize; the catalytic material is three-dimensional graphite nitrogen doped graphene with high conductivity and multiple unpaired electron catalytic interfaces, and can enhance the generation of singlet oxygen by persulfate ¹ O ₂ ) The effect of (3); the catalytic material provided by the invention can be recycled, is environment-friendly, has no secondary pollution, is wide in applicable pH range, does not need to consume additional energy (such as ultrasound, light, electricity and the like), reduces the cost, has short catalytic time, and has wide practical application prospect.

Description

Catalyst for generating singlet oxygen by targeted activation of persulfate and preparation method and application thereof

Technical Field

The invention relates to the technical field of oxidation treatment of typical new pollutants in water, in particular to a catalyst for generating singlet oxygen by targeted activation of persulfate, and a preparation method and application thereof.

Background

The pollutants in the environmental water body are complex and changeable, the content and the variety of various artificially synthesized organic matters are increased, and the problems of water environment pollution and environmental risk are increased. Among the various synthetic organisms, emerging drugs and personal care products (Pharmaceuticals and personal care products, PPCPs) are particularly prominent in the contamination of aqueous environments, and most PPCPs appear to be difficult to biodegrade. Most of unconsumed PPCPs and metabolites thereof enter sewage plants through municipal pipe networks, but the current conventional biochemical water treatment process has limited PPCPs removal capacity. Therefore, development of novel water treatment technology is urgently needed to remove organic pollutants which are difficult to degrade in water, improve the environmental water quality and reduce the potential ecological health risks.

The Persulfate (PS) advanced oxidation technology has the advantages of strong oxidation capability, wide pH application range, good selectivity, long half-life and the like, and becomes a hot spot technology for removing refractory organic pollutants in environmental water. Studies report that PS can produce five main active substances and are habitually summarized into two major classes: free radical (SO) ₄ ^·- 、OH ^· 、O ₂ ^·- ) Class and non-radical [ ] ¹ O ₂ ETC). The progress of the study of the two classes of reaction pathways was analyzed and summarized and the main differences between the radical and non-radical pathways are shown in table 1. Along with the enrichment of the meaning of the PS advanced oxidation technology, the variety and complexity of the technology mechanism can be found, and the non-radical path provides a new research thought for the efficiency and mechanism of the PS advanced oxidation technology for degrading the PPCP.

TABLE 1 Properties of free radical and non-radical active species

The precondition for PS production of active species is the need for activation. Different activation techniques also determine the composition of the active species. The activating species of PS include the use of external energy activators (e.g., ultrasound, heat, light), transition metal (e.g., fe, co, mn) based catalysis (both homogeneous and heterogeneous), chemical activators (e.g., bases, phenols, and quinones), and carbon-based catalysis (heterogeneous). The novel PS activation technology based on the nonmetallic carbon-based catalytic material can effectively degrade organic pollutants, is efficient, economical, environment-friendly and easy to prepare, and has obvious advantages, so that the synthesis and modification of the novel nonmetallic carbon-based material become a novel research hot spot.

Along with ¹ O ₂ Extensive detection of (singlet oxygen) in nitrogen doped carbon material activated PS systems, utilization ¹ O ₂ The efficacy and mechanism of PPCP degradation has also attracted considerable attention. Currently, most nitrogen-doped carbon materials are prepared by adding external nitrogen sources (e.g., melamine, ammonium nitrate, and urea) followed by an annealing process (appl. Catalyst. B Environ,2018, 225:243-257.). These methods generally have the problems of complicated preparation technology, unstable nitrogen atom doping, and the like. In addition, nitrogen-doped carbon-activated PS can produce SO ₄ ^·- 、 ¹ O ₂ And ETC, how to enhance by regulation of catalytic sites ¹ O ₂ Still further research is required for the generation of (c).

Disclosure of Invention

The invention aims to provide a catalyst for generating singlet oxygen by targeted activation of persulfate, and a preparation method and application thereof. Polyaniline (PANI) is synthesized on the surface of graphene oxide in situ, and then thermal reduction annealing is carried out in an inert environment to prepare high-conductivity nitrogen-doped graphene, so thatThe catalytic material has the function of activating sulfate production ¹ O ₂ And in (2) ¹ O ₂ Under the action of the catalyst, PPCP pollutants, especially diclofenac, are deeply degraded. The catalyst has good recycling effect, reduces the running cost, has wide pH application range, and provides wide application prospect for PPCP pollutants in urban sewage systems.

In order to achieve the above purpose, the present invention provides the following technical solutions:

one of the technical schemes of the invention is as follows: the preparation method of the catalyst for generating singlet oxygen by targeted activation of persulfate comprises the following steps:

(1) Respectively dissolving aniline and ammonium persulfate in a hydrochloric acid solution to obtain an aniline solution and an ammonium persulfate solution;

(2) Freezing ammonium persulfate solution, pouring graphene oxide solution, and freezing to obtain a system M;

(3) Pouring the precooled aniline solution into a system M for reaction, filtering after the reaction is finished, and washing and drying the obtained solid substance;

(4) Performing thermal reduction on the solid matters obtained after the drying in the step (3) to obtain a catalyst for generating singlet oxygen by targeted activation of persulfate, which is named PANI/RGO ₁₀₀₀ 。

Preferably, the concentration of the hydrochloric acid solution in the step (1) is 1mol/L; the concentration of the aniline solution is 0.2mol/L; the concentration of the ammonium persulfate solution is 0.2mol/L.

Preferably, the concentration of the graphene oxide solution in step (2) is 37.5g/L.

Preferably, the pre-cooling temperature in the step (3) is 4 ℃ and the time is 0.5-3 h; the reaction temperature was 0℃and the reaction time was 9h.

Preferably, the freezing of the ammonium persulfate solution and the graphene oxide solution in step (3) is performed at-18 ℃.

Preferably, the washing in step (3) is an ethanol and water centrifuge washing; the drying condition is 80 ℃ vacuum drying for 24 hours.

Preferably, the thermal reduction in step (4) is performed under an inert atmosphere, and the temperature-increasing procedure of the thermal reduction is as follows: raising the temperature from room temperature to 1000 ℃ at a heating rate of 10 ℃/min, maintaining for 1h, then lowering the temperature to 300 ℃ at an annealing rate of 5 ℃/min, and naturally cooling to room temperature.

More preferably, the thermal reduction is carried out in a tube furnace, the inert atmosphere being achieved by introducing nitrogen at a flow rate of 1L/min.

The second technical scheme of the invention is as follows: a catalyst for targeted activation of persulfate to generate singlet oxygen, which is prepared by the preparation method, is provided.

The third technical scheme of the invention: the application of the catalyst for generating singlet oxygen by targeting activated persulfate in degrading PPCP pollutants is provided.

Preferably, the PPCP-based contaminant includes one or more of diclofenac, ofloxacin, sulfamethoxazole, phenol, bisphenol a, ibuprofen, and carbamazepine.

The beneficial technical effects of the invention are as follows:

the catalytic material PANI/RGO provided by the invention ₁₀₀₀ The preparation method has the advantages of simple operation, mild condition, strong repeated operability and easy realization; the catalytic material is three-dimensional graphite nitrogen doped graphene with high conductivity and multiple unpaired electron catalytic interfaces, and can enhance persulfate production ¹ O ₂ The effect of (3); the catalytic material provided by the invention can be recycled, is environment-friendly, has no secondary pollution, is wide in applicable pH range, does not need to consume additional energy (such as ultrasound, light, electricity and the like), reduces the cost, has short catalytic time, and has wide practical application prospect.

The homogeneous catalyst has the problems of secondary pollution and high economic cost in the activated PS system, and the metal heterogeneous catalyst has the problem of metal leakage in the activated PS system. The catalyst for generating singlet oxygen by targeted activation of persulfate can selectively activate PS to generate ¹ O ₂ And deeply degrading the heterogeneous carbon-based catalyst of PPCP pollutants. The catalyst has the advantages of small dosage, convenient operation and wide applicable pH range.

Drawings

FIG. 1 shows PANI/GO, PANI/RGO prepared in example 1 ₁₀₀₀ And SEM images of PANI prepared in example 2; wherein a is SEM image of PANI, b is SEM image of PANI/GO, c is PANI/RGO ₁₀₀₀ SEM images of (a).

FIG. 2 shows PANI/RGO prepared in example 1 ₁₀₀₀ And XRD pattern of PANI prepared in example 2.

FIG. 3 shows PANI/RGO prepared in example 1 ₁₀₀₀ Wherein a is XPS total spectrum, b is C1s fine spectrum and C is N1s fine spectrum.

FIG. 4 shows PANI/RGO prepared in example 1 ₁₀₀₀ Conductivity map and PANI/RGO at different pressures ₁₀₀₀ Wherein a is a conductivity map and b is an electron paramagnetic spectrum.

FIG. 5 is PANI/RGO in example 4 ₁₀₀₀ The results of the active species quenching experiments in the PDS/DCF system are shown.

FIG. 6 shows the EPR test of PANI/RGO in example 4 ₁₀₀₀ Results of active species in PDS System, where a is OH ^· And SO ₄ ^·- B is O ₂ ^·- C is the detection result of ¹ O ₂ Is a result of detection of (a).

FIG. 7 is PANI/RGO in example 5 ₁₀₀₀ Kinetics of degradation of different concentrations of DCF in PDS/DCF systems.

FIG. 8 is PANI/RGO in example 6 ₁₀₀₀ Kinetics of degradation of DCF at different pH values in a PDS/DCF system.

FIG. 9 is PANI/RGO at different PDS concentrations in example 7 ₁₀₀₀ Mineralization properties of the DCF are degraded by the PDS system.

FIG. 10 is a graph of PANI/RGO in an actual body of water simulated by common ions in example 8 ₁₀₀₀ Adsorption degradation effect of PDS System to degrade DCF, wherein a is 10mM Cl ^- 、Br ^- 、SO ₄ ^2- B is 100mM Cl ^- 、Br ^- 、SO ₄ ^2- Simulated water body, c is CO ₃ ^2- 、HCO ₃ ^- Simulated water body, d is NO ₃ ^- 、NO ₂ ^- 、NH ₄ ⁺ And (5) simulating a water body.

FIG. 11 is a graph of the simulation of PANI/RGO in an actual body of water using the common dissolved organics of example 8 ₁₀₀₀ Adsorption degradation effect of degrading DCF by PDS system, wherein a is concentration of each organic matter 10mg L ^-1 B is the concentration of each organic matter of 25mg L ^-1 Is a simulated body of water.

FIG. 12 is PANI/RGO in example 9 ₁₀₀₀ The PDS system has adsorption and degradation effects and mineralization performances on different PPCP organic pollutants, wherein a is the adsorption and degradation effects, and b is the mineralization performances.

Detailed Description

Various exemplary embodiments of the invention will now be described in detail, which should not be considered as limiting the invention, but rather as more detailed descriptions of certain aspects, features and embodiments of the invention. It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

In addition, for numerical ranges in this disclosure, it is understood that each intermediate value between the upper and lower limits of the ranges is also specifically disclosed. Every smaller range between any stated value or stated range, and any other stated value or intermediate value within the stated range, is also encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention.

As used herein, the terms "comprising," "including," "having," "containing," and the like are intended to be inclusive and mean an inclusion, but not limited to.

Example 1

Preparation of a catalyst for targeted activation of persulfate to generate singlet oxygen:

(1) Dissolving 0.3726g of aniline and 0.9128g of ammonium persulfate in 20mL of hydrochloric acid (1M) solution respectively, and uniformly mixing by ultrasonic to obtain 0.2M aniline solution and 0.2M ammonium persulfate solution;

(2) The 0.2M aniline solution is placed in a refrigerator with the temperature of 4 ℃ for precooling for 3 hours; simultaneously pouring 0.2M ammonium persulfate solution into a double-layer screw bottle with 100mL (inner diameter of 40 mm), and placing the bottle in an ethanol water bath environment with temperature of-18 ℃ until the ammonium persulfate solution is completely frozen (2 to 3 hours are needed);

(3) Pouring 20mL of graphene oxide solution containing 0.75g into the frozen ammonium persulfate solution, and continuing to completely freeze (2 to 3 hours) at the temperature of-18 ℃ in a water bath, and marking as a system M;

(4) Pouring the precooled aniline solution into a system M, adjusting the water bath temperature to 0 ℃, and reacting for 9 hours;

(5) After the reaction is finished, filtering the reaction system by using a filter membrane with the diameter of 0.45 mu m to obtain a solid substance, centrifugally washing the solid substance for 5 times by using ethanol and deionized water respectively, and then drying the solid substance in vacuum for 24 hours at 80 ℃, wherein the obtained product is named PANI/GO;

(6) Putting PANI/GO into a tubular furnace for thermal reduction, firstly introducing nitrogen for 10min at a flow of 1L/min to remove oxygen, then heating to 1000 ℃ from room temperature at a heating rate of 10 ℃/min, maintaining at 1000 ℃ for 1 hour, naturally cooling to room temperature after an annealing rate of 5 ℃/min is reached to 300 ℃, grinding a thermal reduction product to pass through a 100-mesh screen after cooling is completed, and obtaining the catalyst for generating singlet oxygen by targeted activation of persulfate, wherein the catalyst is marked as PANI/RGO ₁₀₀₀ Placing into a drier, and storing in dark place.

Example 2

Preparation of Polyaniline (PANI):

(3) Pouring 20mL of the solution containing the ultrapure water into the frozen ammonium persulfate solution, continuing to freeze completely (2 to 3 hours are needed) in a water bath at the temperature of-18 ℃ to obtain a system M1;

(4) Pouring the precooled aniline solution into a system M1, adjusting the water bath temperature to 0 ℃, and reacting for 9 hours;

(5) After the reaction was completed, the reaction system was filtered with a 0.45 μm filter membrane to obtain a solid matter, the solid matter was washed 5 times with ethanol and deionized water by centrifugation, and then dried under vacuum at 80℃for 24 hours, and the obtained product was designated as PANI.

FIG. 1 shows PANI/GO, PANI/RGO prepared in example 1 ₁₀₀₀ And SEM images of PANI prepared in example 2; wherein, a is SEM image of PANI, b is SEM image of PANI/GO, c is PANI/RGO ₁₀₀₀ SEM images of (a).

As can be seen from fig. 1 a, the result of PANI growth in solution without the presence of GO substrate is often a heterogeneous rod-like and sea urchin-like structure. In the presence of GO (b in FIG. 1), the PANI grows on the surface of GO to easily obtain a regular nanowire structure, a large amount of monomers nucleate and grow on the surface of GO to obtain PANI with a burr-like structure, and the PANI is connected with structures on other GO sheets due to freezing, so that the three-dimensional multilayer PANI/GO composite material with good combination of the burr-like and the sheets is finally obtained. After carbonization treatment at 1000 ℃, PANI is melted, the carbon skeleton is destroyed and rearranged, the carbon skeleton is gradually converted into ordered, and the rearranged PANI is well inserted into RGO sheets, so that the RGO sheets are fully peeled off, and a three-dimensional multi-layer structure is shown (c in fig. 1).

As can be seen from fig. 2, three peaks of 2θ in the vicinity of 15 °,20 °,24 ° are typical of the doped polyaniline. Wherein a peak of 20℃represents periodicity parallel to the polymer chain and a peak of 24℃represents regularity perpendicular to the molecular chain, the intensity of the peaks of 24℃being higher than that of 20℃corresponding to highly doped peaksPANI formation in the intermediate oxidation state indicates relatively high crystallinity and conductivity of PANI. PANI/RGO ₁₀₀₀ The XRD of (c) has two broad diffraction peaks centered around 24 ° and 42 °, characterizing the microcrystalline structure carbon of weak graphitization characteristics, and the relatively broad signal indicates that the carbon materials are both substantially amorphous structures.

FIG. 3a shows PANI/RGO ₁₀₀₀ C, N, O in the material is 90.53at%, 5.84at% and 3.63at%. Then carrying out fine spectrum analysis on C1s and N1s, wherein the structure and the composition of the functional group are shown as b and C in figure 3, the N doping type mainly comprises pyridine nitrogen, pyrrole nitrogen, graphite nitrogen and nitrogen oxide, the N doping type and the content are obtained according to peak-splitting spectrum fitting, and the content order is graphite nitrogen (3.22 at%)>Nitrogen oxides (1.22 at%)>Pyridine nitrogen (0.75 at%)>Pyrrole nitrogen (0.65 at%).

From FIG. 4a, PANI/RGO is shown ₁₀₀₀ Under the measurement condition of 3MPa, the conductivity is 178000 S.cm ^-1 . FIG. 4 b shows PANI/RGO ₁₀₀₀ The number of unpaired electrons on the surface is 7.292 ×10 ¹⁶ spins·g ^-1 。

To sum up, PANI/RGO ₁₀₀₀ Is a three-dimensional multi-level carbon-based catalyst with high conductivity, high surface defect and high graphite nitrogen doping.

Example 4

PANI/RGO prepared in example 1 ₁₀₀₀ As a catalyst, potassium Persulfate (PDS) is used as an oxidant, diclofenac (DCF) is used as a typical PPCP pollutant, and PANI/RGO is explored ₁₀₀₀ Main active substances in PDS catalytic systems.

Respectively selecting methanol (MeOH), tertiary Butanol (TBA), sodium azide (NaN) ₃ ) 1, 4-p-benzeneQuinone (BQ) and sodium perchlorate (NaClO) ₄ ) As active material probes. Wherein MeOH can be simultaneously combined with SO ₄ ^·- (k＝2.5×10 ⁷ M ^-1 s ^-1 ) And OH (OH) ^· (k＝9.7×10 ⁸ M ^-1 s ^-1 ) Reacting; TBA can be combined with OH only ^· (k＝(3.8-7.6)×10 ⁸ M ^-1 s ^-1 ) Reacting; BQ (k=9.0×10) ⁸ M ^-1 s ^-1 ) Can be used as O ₂ ^·- Is a quencher of (2); naN (NaN) ₃ (k＝1.0×109M ^-1 s ^-1 ) Can be used as ¹ O ₂ Is characterized by the reactants; naClO ₄ The ionic strength can be increased without affecting the decomposition of PS, and thus can be used as a quencher for electron transfer to demonstrate the presence or absence of electron transfer mediated non-radical pathways in the system.

Determination of reactive oxygen Species (SO) generated in the System Using Bruker A300 electron spin resonance spectrometer (EPR) ₄ ^·- 、OH ^· 、O ₂ ^·- 、 ¹ O ₂ ) DMPO and TEMP were used as capture agents. The specific operation steps are as follows: first, a stock solution of 100mM DMPO and TEMP capture agent, a catalyst solution of 0.2g/L, and a stock solution of 50mM PDS were prepared. Then 250. Mu.L of the trapping agent stock solution was placed in a 1.5mL centrifuge tube, then 250. Mu.L of the catalyst solution was added, then 2.5. Mu.L of the PDS stock solution was added, and the mixture was thoroughly mixed and the time was started. At 5min of reaction, samples were taken with a capillary glass tube and placed into the cavity of the EPR for testing.

PANI/RGO ₁₀₀₀ The results of the active species quenching experiments in the/PDS/DCF system are shown in FIG. 5.

FIG. 5 shows that the same PANI/RGO is achieved without any additional quencher ₁₀₀₀ In the DCF degradation experiments carried out under the dosage of PDS and DCF as the comparison experiments, the degradation rate of DCF is 76.8 percent, and the quasi-first-order reaction constant is 0.3243min ^-1 。

(1) The degradation rate of DCF after MeOH and TBA addition was 75.0% and 75.8%, and the reaction rate constants were 0.2841 and 0.3283min ^-1 No obvious inhibition, thus primary determination of the main active substances in the systemNot SO ₄ ^·- And OH (OH) ^· ；

(2) The degradation rate of DCF was slightly reduced (73.3%) after BQ addition, but the reaction rate constant was significantly reduced (0.1258 min) ^-1 ) Preliminary determination of the presence of O in the System ₂ ^·- ；

(3)NaN ₃ The degradation rate of DCF after the addition is reduced to 68.9 percent, and the reaction rate constant is reduced to 0.1137 minutes ^-1 Determining the presence in the system ¹ O ₂ ；

(4)NaClO ₄ The degradation rate of DCF after addition is 77.2%, and the reaction rate constant is reduced to 0.2227min ^-1 It was initially determined that ETC may be present in the system, but not the primary active.

For PANI/RGO ₁₀₀₀ EPR analysis was performed by the/PDS system, the results are shown in FIG. 6, wherein a is OH and SO ₄ ^·- B is O ₂ ^·- C is the detection result of ¹ O ₂ Is a result of detection of (a). As shown in figure 6 of the drawings, ¹ O ₂ most pronounced, O ₂ ^·- And SO ₄ ^·- The response signal of (2) is relatively weak.

To evaluate the different active species in PANI/RGO ₁₀₀₀ Contribution in DCF degradation in PDS system the present invention brings the pseudo first order kinetic constants of the quenching experiments into

equations

1, 2, 3, 4. The result of the calculation is that, ¹ O ₂ in PANI/RGO ₁₀₀₀ Contribution ranking in the/PDS/DCF architecture is first (64.9%), followed by O ₂ ^·- (61.2%) and ETC (31.3%).

λ[ ¹ O ₂ ]＝(k ₀ -k ₁ )/k ₀ (1)

λ[ETC]＝(k ₀ -k ₃ )/k ₀ (3)

Example 5

PANI/RGO prepared in example 1 ₁₀₀₀ As a catalyst, potassium Persulfate (PDS) was used as an oxidant to study the adsorption and degradation effects of the catalyst on Diclofenac (DCF) which is an organic pollutant at different concentrations.

(1) 0.2mM DCF solution, 100mM PDS solution, 100mM PBS buffer solution at pH=7 was prepared and used as stock solution;

(2) Adding a specific volume of DCF and PBS stock solution into a reactor by taking a brown serum bottle as the reactor, fixing the volume to 100mL, and putting the mixture into the serum bottle, wherein the final concentration of PBS is 5mM, and the concentration of DCF is 0.01, 0.025, 0.05, 0.08 and 0.10mM respectively;

(3) Adding a rotor into a serum bottle, and then placing the serum bottle into a water bath temperature control stirrer, wherein the temperature is controlled to be 25 ℃, and the magnetic stirring speed is 400rpm/min;

(4) Then 10mg of catalyst PANI/RGO ₁₀₀₀ After being placed in the solution and the pollutant is adsorbed and balanced (about 15 min), the PDS stock solution with the concentration of 0.25mL-100mM is added to start the catalytic reaction, and the fixed point sampling analysis is carried out.

PANI/RGO ₁₀₀₀ The degradation kinetics of different concentrations of DCF in the/PDS/DCF system are shown in FIG. 7. As can be seen from FIG. 7, PANI/RGO ₁₀₀₀ Due to the excellent specific surface area (257.0 m ² ·g ^-1 ) Has remarkable adsorption removal capability on DCF. When a lower concentration of DCF (0.01 mM) was added, PANI/RGO ₁₀₀₀ The adsorption removal rate of DCF was 81.0%. When DCF (0.01 mM) was added at a relatively high concentration, the adsorption removal rate of DCF was 16.2%, and the adsorption capacity increased as the amount of catalyst added increased. In PANI/RGO ₁₀₀₀ In the/PDS system, the degradation of DCF follows quasi-first order kinetics (Table 2). PANI/RGO ₁₀₀₀ The degradation rate of activated PMS to degrade DCF decreases with increasing DCF concentration; the removal efficiency of DCF is 100% in the adsorption of 15min and the degradation time of 30min in the range of 2.5-25 of PDS/DCF.

TABLE 2PANI/RGO ₁₀₀₀ Quasi-first order kinetic parameters for activating PDS to degrade DCF

Example 6

PANI/RGO prepared in example 1 ₁₀₀₀ As a catalyst, potassium Persulfate (PDS) was used as an oxidizing agent to investigate the adsorption and degradation effects of pH on Diclofenac (DCF), an organic pollutant.

(1) The conditions are the same as in example 5, step (1);

(2) Adding a specific volume of DCF and PBS stock solution into a reactor by using a brown serum bottle as the reactor, regulating the pH value to (5, 7, 9 and 11) by using a specific volume of diluted hydrochloric acid and sodium hydroxide, fixing the volume to 100mL, and putting into the serum bottle, wherein the concentration of DCF is 0.08mM and the concentration of PBS is 5mM respectively;

(3) The conditions are the same as in example 5, step (3);

(4) The conditions were the same as in example 5, step (4).

The pH value can influence the zeta potential of the catalyst, the dissociated form of DCF and the activation efficiency of PDS, so PANI/RGO at different pH values is needed ₁₀₀₀ The efficiency of adsorbing DCF and activating PDS to degrade DCF was evaluated.

PANI/RGO ₁₀₀₀ The kinetics of DCF degradation at different pH values in the PDS/DCF system is shown in fig. 8. As shown in fig. 8, the adsorption removal rates of DCF were 28.0%, 23.1%, 18.7%, and 16.9%, respectively, with increasing pH; after 30min of degradation, the removal efficiency of DCF can reach 100%, which shows that PANI/RGO under acidic and alkaline conditions ₁₀₀₀ The PDS oxidation system has high oxidation efficiency.

Example 7

PANI/RGO prepared in example 1 ₁₀₀₀ As a catalyst, potassium Persulfate (PDS) was used as an oxidant to investigate the mineralization properties of the oxidation system on the organic contaminant Diclofenac (DCF).

(1) The conditions are the same as in example 5, step (1);

(2) Adding a specific volume of DCF and PBS stock solution into a reactor by using a brown serum bottle as the reactor, fixing the volume to 100mL, and putting the mixture into the serum bottle, wherein the concentration of DCF is 0.08mM and the concentration of PBS is 5mM finally;

(3) The conditions are the same as in example 5, step (3);

(4) Then 10mg of catalyst PANI/RGO ₁₀₀₀ After being placed into the solution and the pollutant is adsorbed and balanced (about 15 min), the PDS stock solution of 0.25mL, 0.30mL and 0.40mL-100mM is respectively added to start the catalytic reaction, and the total organic carbon TOC of the solution is measured by fixed-point sampling analysis.

FIG. 9 PANI/RGO at different PDS concentrations ₁₀₀₀ Mineralization properties of the DCF are degraded by the PDS system. FIG. 9 shows that in PANI/RGO ₁₀₀₀ In the/PDS oxidized DCF system, when the degradation time is 30min, the initial concentration of DCF is 0.08mM, and when the initial concentration of PDS is 0.25mM, the DCF is not considered, only TOC in the solution after adsorption equilibrium is considered for removal, and the mineralization rate of the DCF is 89.8%; when the addition concentration of PDS is 0.30mM, the mineralization rate of DCF is 92.9%; when the PDS concentration was 0.40mM, the mineralization rate of DCF was 92.9%.

Compared with the system with higher mineralization efficiency of DCF in the current research report (Table 3), PANI/RGO ₁₀₀₀ The PDS oxidation system has more efficient mineralization capability.

TABLE 3 mineralization Properties of different Oxidation systems to degrade DCF

Oxidation system	Active species	Mineralization rate	Reference to the literature
				PANI/RGO ₁₀₀₀ /PDS	¹ O ₂ 、O ₂ ^·-	92.9％	This study
UV/PDS	SO ₄ ^·-	32.0％	Ecotoxicol.Environ.Saf.,2017,141:139-147.
				Fe ⁰ /PDS	OH ^· 、SO ₄ ^·-	81.5％	WaterAirSoilPollut,2020,231(6):1-13.
Bi _7.53 Co _0.47 O _11.92 /PMS	¹ O ₂ 、O ₂ ^·-	82.1％	JCleanProd,2022,365:132781.
				MnO ₂ -Bi ₂ O ₃ /PMS	O ₂ ^·- 、 ¹ O ₂	70.1％	Chem.Eng.J,2022,433:133742

Example 8

PANI/RGO prepared in example 1 ₁₀₀₀ As a catalyst, potassium Persulfate (PDS) is used as an oxidant, and the adsorption and degradation effects of an oxidation system on Diclofenac (DCF) under different complex actual water environments are studied.

(1) Preparation of 0.2mM DCF solution, 100mM PDS solution, 100mM PBS buffer solution at ph=7, 1M ion model (KCl, KBr, K ₂ SO ₄ 、NaNO ₂ 、KNO ₃ 、(NH ₄ ) ₂ SO ₄ 、Na ₂ CO ₃ 、NaHCO ₃ ) Solution, 100mg L ^-1 Is used as a stock solution;

(2) Adopting a brown serum bottle as a reactor, adding a specific volume of DCF, PBS, an ion model substance or a soluble organic substance stock solution into the reactor, fixing the volume to 100mL, and putting into the serum bottle, wherein the final concentration of PBS is 5mM, and the concentration of DCF is 0.08mM;

FIG. 10 shows PANI/RGO in a real water body simulated by common ions ₁₀₀₀ Adsorption degradation effect of PDS System to degrade DCF, wherein a is 10mM Cl ^- 、Br ^- 、SO ₄ ^2- B is 100mM Cl ^- 、Br ^- 、SO ₄ ^2- Simulated water body, c is CO ₃ ^2- 、HCO ₃ ^- Simulated water body, d is NO ₃ ^- 、NO ₂ ^- 、NH ₄ ⁺ And (5) simulating a water body.

FIG. 10 shows the addition of 100mM Cl ^- 、Br ^- 、SO ₄ ^2- 、5mM CO ₃ ^2- 、5mM HCO ₃ ^- 、10mM NO ₃ ^- 、10mM NO ₂ ^- 、10mM NH ₄ ⁺ After that, the removal rate of DCF can still reach 100% in 30min, and the effect on DCF adsorption is less.

In actual water treatment, the composition of water quality is very complex, and the concentration of natural organic matters is highFor example, DOM is complex in composition, and contains not only low-molecular-weight free amino acids, saccharides and organic acids, but also high-molecular-weight humus, amino sugars and polyphenols, and the reaction of DOM with an oxidant increases the consumption of the oxidant, reduces the treatment efficiency of the oxidant on target pollutants, and for carbon-based catalysts, it is also necessary to evaluate whether the activation of PDS is hindered by DOM adsorption. Therefore, tannic acid (polyphenol), vanillin (aldehydes), humic acid (rich in carboxyl and hydroxyl groups) and fulvic acid (a core component of soil humus) are selected as model objects of DOM, and organic pairs PANI/RGO with different concentrations are studied ₁₀₀₀ PDS removes the effect of DCF.

FIG. 11 is a schematic illustration of a common dissolved organic matter simulating PANI/RGO in an actual body of water ₁₀₀₀ Adsorption degradation effect of degrading DCF by PDS system, wherein a is concentration of each organic matter 10mg L ^-1 B is the concentration of each organic matter of 25mg L ^-1 Is a simulated body of water.

FIG. 11 shows that 10 and 25 mg.L ^-1 The addition of tannic acid causes PANI/RGO ₁₀₀₀ The adsorption removal rate of DCF is reduced from 23.1% to 13.8% and 10.2%, and the comprehensive removal efficiency (adsorption and degradation) of DCF is reduced from 100% to 42.8% and 9.3%, respectively; adding 10 and 25 mg.L ^-1 PANI/RGO after vanillin ₁₀₀₀ The adsorption removal rate of DCF is respectively reduced from 23.1% to 17.4% and 13.6%, and the comprehensive removal efficiency of DCF is 91.0% and 60.5%;10 mg.L ^-1 And 25 mg.L ^-1 Humic acid addition to PANI/RGO ₁₀₀₀ The adsorption removal rate of DCF is respectively reduced from 23.1% to 15.9% and 11.2%, and the comprehensive removal efficiency of DCF is 86.4% and 65.1%;10 mg.L ^-1 And 25 mg.L ^-1 The addition of fulvic acid causes PANI/RGO ₁₀₀₀ The adsorption removal rate of DCF is reduced from 23.1% to 15.6% and 13.6%, respectively, and the comprehensive removal efficiency of DCF is 88.2% and 61.1%.

Overall, PANI/RGO ₁₀₀₀ The PDS system has good anti-ion interference capability, can continuously and efficiently realize the degradation of target pollutants, but the target organic matters and macromolecular soluble organic matters have a competitive relationship with the consumption of the oxidant in the oxidation system, thus being unfavorableAnd removing target organic matters.

Example 9

PANI/RGO prepared in example 1 ₁₀₀₀ As a catalyst, potassium Persulfate (PDS) is used as an oxidant, and the adsorption and degradation effects and mineralization performances of an oxidation system on different PPCP organic pollutants are studied.

(1) Preparation of 100mg L ^-1 For stock solutions, PPCP solutions of (diclofenac (DCF), ofloxacin (OFL), sulfamethoxazole (SMZ), phenol (PHZ), bisphenol a (BPA), ibuprofen (IBP), carbamazepine (CBZ)), 100mM PDS solution, 100mM PBS buffer solution at ph=7;

(2) Adopting a brown serum bottle as a reactor, adding a specific volume of PPCP and PBS stock solution into the reactor, fixing the volume to 100mL, putting into the serum bottle, and finally setting the concentration of PBS to be 5mM and the concentration of PPCP to be 10 mg.L ^-1 ；

(4) Then 10mg of catalyst PANI/RGO ₁₀₀₀ After being placed into the solution and the pollutant is adsorbed and balanced (about 15 min), the PDS stock solution with the concentration of 0.25mL-100mM is added to start the catalytic reaction, and the PPCP concentration and the TOC concentration are analyzed by fixed point sampling.

FIG. 12 is a PANI/RGO ₁₀₀₀ The PDS system has adsorption and degradation effects and mineralization performances on different PPCP organic pollutants, wherein a is the adsorption and degradation effects, and b is the mineralization performances.

FIG. 12 shows PANI/RGO ₁₀₀₀ PDS-dominant ¹ O ₂ The system can realize the high-efficiency removal of 4 PPCPs of phenol, bisphenol A, diclofenac and ofloxacin. PHE and BPA were used as phenolic representatives, and mineralization rates of 89.7% and 98.8% were achieved during the reaction. The degradation rate of DCF and OFL is higher than that of phenolic contaminants, mainly because DCF and OFL are found in PANI/RGO ₁₀₀₀ The adsorption removal rate of the surface reaches 41.2% and 47.6%, so that the concentration of residual pollutants in the solution is low. In PANI/RGO ₁₀₀₀ In the/PDS system, the mineralization rate of DCF was 80.8%, while the mineralization rate of OFL was only 5.9%. SMX removal rate was 29.5%, and oreThe conversion rate reaches 40.5 percent. Adsorption of IBP and CBZ has little effect on PDS activation, but PANI/RGO ₁₀₀₀ The degradation efficiency of the/PDS system is almost negligible for both. At the position of ¹ O ₂ And the PPCP pollutants with phenolic functional groups and carboxylic functional groups are selectively and efficiently degraded in a dominant degradation system.

The above embodiments are only illustrative of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention, and various modifications and improvements made by those skilled in the art to the technical solutions of the present invention should fall within the protection scope defined by the claims of the present invention without departing from the design spirit of the present invention.

Claims

1. A preparation method of a catalyst for generating singlet oxygen by targeted activation of persulfate comprises the following steps:

(4) And (3) thermally reducing the dried solid substance in the step (3) to obtain the catalyst for generating singlet oxygen by targeted activation of persulfate.

2. The method according to claim 1, wherein the concentration of the hydrochloric acid solution in the step (1) is 1mol/L; the concentration of the aniline solution is 0.2mol/L; the concentration of the ammonium persulfate solution is 0.2mol/L.

3. The method according to claim 1, wherein the concentration of the graphene oxide solution in the step (2) is 37.5g/L.

4. The method of claim 1, wherein the pre-cooling in step (3) is at a temperature of 4 ℃; the reaction temperature was 0℃and the reaction time was 9h.

5. The method according to claim 1, wherein the thermal reduction in step (4) is performed under an inert atmosphere, and the temperature-increasing procedure of the thermal reduction is as follows: raising the temperature from room temperature to 1000 ℃ at a heating rate of 10 ℃/min, maintaining for 1h, then lowering the temperature to 300 ℃ at an annealing rate of 5 ℃/min, and naturally cooling to room temperature.

6. The preparation method according to claim 5, wherein the thermal reduction is performed in a tube furnace, the inert atmosphere is achieved by introducing nitrogen gas, and the flow rate of nitrogen gas is 1L/min.

7. A catalyst for the targeted activation of persulfates to form singlet oxygen prepared according to the preparation method of any one of claims 1 to 6.

8. Use of the catalyst for targeted activation of persulfate to generate singlet oxygen according to claim 7 for degradation of PPCP-like contaminants.

9. The use according to claim 8, wherein the PPCP-like contaminant comprises one or more of diclofenac, ofloxacin, sulfamethoxazole, phenol, bisphenol a, ibuprofen, and carbamazepine.